Windows reverseme – nothing tricky, just a sort of complicated validation process. This was originally from crackmes.de, mirror of the executable here.

The easiest thing in the world is to get this thing to validate. Just run it and put a breakpoint at 00401288, and look at the value in 00406749. That’s it! You’re validated.

A lot more tricky was writing the keygen. To do it, I just stepped through the code very slowly, and duplicated the logic. ugh.

Ok, now here is my keygen of the executable. To simplify things, I just considered usernames that are 5 chacters long. Note all the mods. Longer usernames will work, but will require minor mods to the keygen (and I didn’t have the patience to step through the code again).